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      All our courses are engaging, interactive and fun! Whether formal training or simply looking to brush up, we take online learning to the next level.

      • Sailing EssentialsFreeA free course great for anyone who spends time on the water.
      • Essential Navigation & SeamanshipRYA course for beginners. Learn charts, tides, pilotage, and core seamanship with simple practice tasks.
      • Day Skipper TheoryMost PopularRYA course for inshore skippers. Plan day passages using chartwork, tides, weather, and COLREGs.
      • Coastal Skipper / Yachtmaster® TheoryComing SoonRYA course for advanced navigation and passage planning. Work with secondary ports, tidal streams, and offshore weather.
      • SRC (VHF) Marine Radio CourseRYA Short Range Certificate radio course. Study online, then take the practical exam with an RYA assessor.
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      Are you looking for something nautical related? Our directory is an extensive list of courses and places associated with the marine industry. Hop over and search now.

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        Find anywhere nautical, including marinas & training centres. If it exists, we’ve got it listed!
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  • Know-How

      We believe every day’s a school day on a boat! That’s why we built Nautical Know-How, dedicated to answering your questions. Even better, if it can’t answer your question immediately, you can request it, and we’ll add it to our knowledge base.

      • Nautical Terms & Terminology
        Understanding the language of the marine world is like trying to learn a pirate’s secret code while juggling fish. Let us explain why a sheet isn’t for your bed, why “heave ho” doesn’t mean throw up (most of the time), and why “dead reckoning” is surprisingly less ominous than it sounds.
      • Why do we have tides?
        Have you ever wondered what causes the tides? Check out this video, which introduces the forces that create the tides we experience on Earth.
      • What causes our weather?
        A video introducing the drivers behind our weather, part of our RYA Day Skipper & RYA Coastal Skipper / Yachtmaster® Offshore theory courses.
      • Buoyage Flashcards
        Flashcards designed to help remember the buoys in the IALA system. If you want to learn them in detail, our module ‘Getting in and out of harbour‘, covers the IALA system and different buoys used.
      • Interactive Rule Book (COLREGs / IRPCS)
        Whether you’re a novice sailor or a seasoned skipper, we can help you navigate the IRPCS confidently and clearly. Our easy-to-use, easy-to-understand, plain English rule book with helpful interpretations of what each rule means.
      • The Salty Sea Blog
        From salty old sea dogs to fresh-faced deckhands, this blog is for anyone who finds peace, adventure, and a bit of mischief on the water. So hoist the main, set your course, and let’s sail into the stories, lessons, and musings that make life on the sea so irresistible.
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Nautical Know How
  • Our Courses

      All our courses are engaging, interactive and fun! Whether formal training or simply looking to brush up, we take online learning to the next level.

      • Sailing EssentialsFreeA free course great for anyone who spends time on the water.
      • Essential Navigation & SeamanshipRYA course for beginners. Learn charts, tides, pilotage, and core seamanship with simple practice tasks.
      • Day Skipper TheoryMost PopularRYA course for inshore skippers. Plan day passages using chartwork, tides, weather, and COLREGs.
      • Coastal Skipper / Yachtmaster® TheoryComing SoonRYA course for advanced navigation and passage planning. Work with secondary ports, tidal streams, and offshore weather.
      • SRC (VHF) Marine Radio CourseRYA Short Range Certificate radio course. Study online, then take the practical exam with an RYA assessor.
  • Directory

      Are you looking for something nautical related? Our directory is an extensive list of courses and places associated with the marine industry. Hop over and search now.

      • Places
        Find anywhere nautical, including marinas & training centres. If it exists, we’ve got it listed!
      • Courses
        We help you navigate through the complex world of training and help find what’s best for you.
  • Know-How

      We believe every day’s a school day on a boat! That’s why we built Nautical Know-How, dedicated to answering your questions. Even better, if it can’t answer your question immediately, you can request it, and we’ll add it to our knowledge base.

      • Nautical Terms & Terminology
        Understanding the language of the marine world is like trying to learn a pirate’s secret code while juggling fish. Let us explain why a sheet isn’t for your bed, why “heave ho” doesn’t mean throw up (most of the time), and why “dead reckoning” is surprisingly less ominous than it sounds.
      • Why do we have tides?
        Have you ever wondered what causes the tides? Check out this video, which introduces the forces that create the tides we experience on Earth.
      • What causes our weather?
        A video introducing the drivers behind our weather, part of our RYA Day Skipper & RYA Coastal Skipper / Yachtmaster® Offshore theory courses.
      • Buoyage Flashcards
        Flashcards designed to help remember the buoys in the IALA system. If you want to learn them in detail, our module ‘Getting in and out of harbour‘, covers the IALA system and different buoys used.
      • Interactive Rule Book (COLREGs / IRPCS)
        Whether you’re a novice sailor or a seasoned skipper, we can help you navigate the IRPCS confidently and clearly. Our easy-to-use, easy-to-understand, plain English rule book with helpful interpretations of what each rule means.
      • The Salty Sea Blog
        From salty old sea dogs to fresh-faced deckhands, this blog is for anyone who finds peace, adventure, and a bit of mischief on the water. So hoist the main, set your course, and let’s sail into the stories, lessons, and musings that make life on the sea so irresistible.
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Glossary

Nautical chart abbreviations are like the secret code of the seas—except instead of buried treasure, they lead to rocks, buoys, and mysterious dashed lines that scream, 'Don’t sail here.' Learning them can feel like cracking a pirate’s encrypted diary, but don’t worry, matey! With clever tools, quirky mnemonics, and a splash of humour, we’ll help you go from 'What’s "FOUL" mean? to confidently navigating the “Wk” wrecks and “Fl G” flashes like a salty sea captain. Think of it as Rosetta Stone, but for avoiding sandbanks!
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Results: 1147
  • Term
    Definition
  • Abbreviation, Light Characteristic Occulting (Oc)

    A light with more light than dark (is on for longer than it is off).

    Occulting refers to a type of navigational light in which the light is...

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  • General Nautical Terminology Ocean Data Acquisition System (ODAS)

    The Ocean Data Acquisition System (ODAS) is a system used to collect, process, and transmit various types of oceanographic data. This system...

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  • Flag / Pennant, Signals & Communication Code Flag Oscar (O)

    The International Maritime Signal Flag Oscar.

    Meaning

    Man overboard. (Often attached to the Danbuoy pole on boats.)
    The semaphore flag.

  • General Nautical Terminology ODAS

    The Ocean Data Acquisition System (ODAS) is a system used to collect, process, and transmit various types of oceanographic data. This system...

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  • General Nautical Terminology Officer of the Watch (OOW)

    The designated officer responsible for the safe navigation and operation of a vessel during their assigned watch period. 

    The Officer of the...

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  • General Nautical Terminology Offshore

    The area of the sea that is away from the coast, typically beyond the immediate inshore waters, and often associated with deeper waters and...

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  • Courses, RYA Offshore Personal Survival (RYA/World Sailing)The Offshore Personal Survival course is an intensive program designed for sailors participating in offshore and ocean races. Participants learn... More Details
  • General Nautical Terminology OilskinsWaterproof clothing worn in foul weather
  • Flag Semaphore, Signals & Communication Letter O (Flag Semaphore)
    Flag semaphore indicating the letter O.

    Flag semaphore indicating the letter O.

  • Morse Code, Signals & Communication Letter O (Morse Code)

    International Morse Code sequence representing the letter O.

  • General Nautical Terminology OnshoreWind blowing towards the land or “not at sea”.
  • General Nautical Terminology, Parts of a Boat On the Port Bow

    Refers to something located in the forward left quadrant of a vessel, between directly ahead and 90 degrees to the port (left) side.

    "On the...

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  • General Nautical Terminology On the Port QuarterAt an angle to the stern of your vessel, but abaft the beam, to the left
  • General Nautical Terminology, Parts of a Boat On the Starboard Bow

    Refers to a position or object located forward of the vessel and to the right-hand side when facing the bow (front) of the ship.

    "On the...

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  • General Nautical Terminology, Parts of a Boat On the Starboard Quarter

    The area of a vessel located towards the rear (aft) on the right-hand side when facing forward.

    The phrase "on the starboard quarter" is a...

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  • General Nautical Terminology OOW

    The designated officer responsible for the safe navigation and operation of a vessel during their assigned watch period. 

    The Officer of the...

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  • Phonetic Alphabet, Signals & Communication Oscar

    Pronounced: OSS-cah

    The term for the letter O in the NATO Phonetic Alphabet.

  • General Nautical Terminology, Parts of a Boat Outhaul

    A line or tackle system used to adjust the tension and position of the sail's clew along the boom, affecting the sail's shape and...

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  • General Nautical Terminology OverfallsTurbulent waters where is a sudden change in depth or where two tidal streams meet
  • General Nautical Terminology Overhand loop

    A loop that crosses on top of the standing part of a rope when tying a knot.

  • General Nautical Terminology PainterThe line at the bow of a dinghy
  • General Nautical Terminology, Safety, Signals & Communication Pan Pan

    An internationally recognised maritime urgency signal used in radio communications to indicate a situation that is urgent but does not pose an...

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  • Phonetic Alphabet, Signals & Communication Papa

    Pronounced: pah-pah

    The term for the letter P in the NATO Phonetic Alphabet.

  • General Nautical Terminology, Safety Parachute Flare

    A pyrotechnic distress signal that, when launched, ascends to a high altitude before deploying a parachute to slow its descent while emitting a...

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  • General Nautical Terminology Parallel RulesNavigational instrument used in conjunction with the compass rose on the chart to transfer bearings and courses to plot a vessel’s position
  • General Nautical Terminology, Navigation, Safety Passage

    A journey or route taken by a vessel from one location to another, often across open water or between specific points such as harbours or...

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  • General Nautical Terminology, Navigation, Safety Passage Plan

    A detailed, structured navigational strategy outlining the safest and most efficient route for a vessel from departure to destination,...

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  • General Nautical Terminology Pay Off

    The action or process of a vessel's bow turning away from the wind, often due to wind or rudder adjustments.

    When a vessel "pays off," it is...

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  • General Nautical Terminology Pay OutTo let out a line or rope gradually
  • Flag / Pennant, Signals & Communication Code Flag Papa (P)

    The International Maritime Signal Flag Papa.

    Meaning

    The Blue Peter.
    In harbour: All persons should report on board as the vessel is...

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  • General Nautical Terminology, Navigation PDOP

    Measurement of the geometric strength of satellite configuration in a Global Navigation Satellite System (GNSS) receiver.

    It quantifies the...

    More Details
  • General Nautical Terminology Perling

    The small, gentle ripples or wavelets that form on the surface of the water, typically caused by light winds or minor disturbances.

    Perling...

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  • General Nautical Terminology, Safety Personal Flotation Device (PFD)


    A piece of equipment designed to assist a person in staying afloat in water by providing buoyancy.

    A Personal Flotation Device (PFD), commonly...

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  • General Nautical Terminology, Safety Personal Locator Beacon (PLB)

    A compact, portable device used to transmit a distress signal via satellite to alert search and rescue services in emergencies at sea.

    A...

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  • Courses, RYA Personal Watercraft ProficiencyThe RYA Personal Watercraft Proficiency course is designed for jet ski operators, covering essential skills for safe and enjoyable use.... More Details
  • General Nautical Terminology, Safety PFD


    A piece of equipment designed to assist a person in staying afloat in water by providing buoyancy.

    A Personal Flotation Device (PFD), commonly...

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  • Phonetic Alphabet, Signals & Communication Phonetic Alphabet

    The Phonetic Alphabet, also known as the International Radiotelephony Spelling Alphabet or NATO phonetic alphabet, is a standardised set of words...

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  • General Nautical Terminology PileA stout timber or metal post driven vertically into the a river or seabed
  • General Nautical Terminology PilotAn expert in local waters who assists vessels entering or leaving harbour; An official publication posting details of, for example, local coasts,... More Details
  • General Nautical Terminology, Navigation Pilotage

    Pilotage is the use of fixed visual references by sight or radar to safely navigate to a destination, usually a port or harbour, with the help of...

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  • General Nautical Terminology PinchTo sail too close to the wind so that the sails lose driving power
  • Did you know?, Nautical Saying Pipe down

    Pipe down is a nautical term meaning to quiet down or cease talking. It is often used as a command on a boat or ship to instruct crew members or...

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  • General Nautical Terminology Pitch

    The angle or inclination of a vessel's bow and stern as it moves up and down in response to waves.

    Pitch is a critical concept in marine...

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  • General Nautical Terminology Pitch Pole

    A capsize where a boat flips longitudinally, usually caused by the bow digging into a wave or sudden deceleration.

    A pitch pole is a dramatic...

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  • General Nautical Terminology, Safety PLB

    A compact, portable device used to transmit a distress signal via satellite to alert search and rescue services in emergencies at sea.

    A...

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  • Flag Semaphore, Signals & Communication Letter P (Flag Semaphore)
    Flag semaphore indicating the letter P.

    Flag semaphore indicating the letter P.

  • Morse Code, Signals & Communication Letter P (Morse Code)

    International Morse Code sequence representing the letter P.

  • General Nautical Terminology PlotTo find a vessels position by laying off bearings on a chart
  • General Nautical Terminology, Weather (Meteorology) Plymouth

    Sea area of the Met Office Shipping Forecast. Spans Plymouth Sound and adjacent waters off southwest England.

    From Plymouth Sound (“mouth of the...

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  • General Nautical Terminology Pontoon

    A pontoon is a flat, buoyant structure used to support a platform, bridge, or boat. It is typically made of metal, plastic, or inflatable...

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  • General Nautical Terminology PoopedSwamped by a high, following sea.
  • General Nautical Terminology, Parts of a Boat Port

    The left-hand side of a vessel when facing forward towards the bow.

    The term "port" is used in maritime navigation to refer to the left side...

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  • General Nautical Terminology Port

    A Harbour or docking facility where vessels load and unload cargo or passengers. 

    A port is a designated location along a coast, river, or...

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  • General Nautical Terminology, Parts of a Boat Port Beam

    The side of a vessel that is perpendicular to its centreline and located on the left-hand side when facing forward towards the bow.

    The term...

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  • General Nautical Terminology, Parts of a Boat Port Bow

    The forward left-hand side of a vessel when facing the bow (front).

    The term "port bow" is a specific designation used in nautical contexts to...

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  • General Nautical Terminology PortholeAn aperture on the hull of a vessel that admits light and, sometimes, air
  • General Nautical Terminology, Weather (Meteorology) Portland

    Sea area of the Met Office Shipping Forecast. Located off the south coast of England, near Portland Bill in Dorset.

    Named for Portland Bill on...

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  • General Nautical Terminology, Navigation Portland Plotter

    A navigational tool used in marine chartwork to measure and plot courses, bearings, and distances on nautical charts.

    The Portland Plotter...

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  • General Nautical Terminology Port of RegistryThe port listed in a vessel’s registration documents and lettered on her stern
  • General Nautical Terminology, Parts of a Boat Port Quarter

    The aft-left section of a vessel when facing forward, located between the port beam and the stern.

    The term "port quarter" is a specific...

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  • General Nautical Terminology Port Tack

    The situation in sailing where the wind is coming over the port (left) side of the vessel, and the boom is positioned on the starboard (right)...

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  • General Nautical Terminology, Navigation Position Dilution of Precision (PDOP)

    Measurement of the geometric strength of satellite configuration in a Global Navigation Satellite System (GNSS) receiver.

    It quantifies the...

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  • Courses, RYA Powerboat AdvancedThe RYA Powerboat Advanced course is designed for experienced powerboaters operating in challenging conditions, including night navigation.... More Details
  • Courses, RYA Powerboat IntermediateThe RYA Powerboat Intermediate course bridges the gap between Level 2 and advanced powerboating. Participants learn navigation, passage planning,... More Details
  • General Nautical Terminology Pratique

    The official permission granted to a vessel by port health authorities, allowing it to enter a port and conduct operations after confirming it is...

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  • General Nautical Terminology, Weather (Meteorology) Precipitation

    Any form of water, such as rain, snow, sleet, or hail, that falls from the atmosphere and reaches the Earth's surface.

    Precipitation is a key...

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  • Did you know?, Nautical Saying Pressed into service

    Pressed into service is the term used to describe the action of the British Navy filling their ships’ crew quotas by kidnapping men off the...

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  • Did you know?, Nautical Saying Press Gangs

    Press gangs were groups of men employed by the British Royal Navy in the 17th to 19th centuries to forcibly recruit individuals into naval...

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  • General Nautical Terminology Prevailing WindThe wind direction that occurs most frequently at a place over a certain period
  • General Nautical Terminology Preventer

    A line or tackle rigged to the boom or spar to prevent unwanted movement, particularly to stop a boom from swinging dangerously during an...

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  • General Nautical Terminology, Navigation Prime Meridian

    The zero-degree longitude line that is the starting point for measuring longitude and dividing the Earth into the Eastern and Western...

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  • General Nautical Terminology, Signals & Communication Procedure Words

    Standardised words or phrases used in marine radio communication to ensure clarity, reduce misunderstandings, and maintain efficient and safe...

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  • Courses, RYA Professional Practices and ResponsibilitiesThe RYA Professional Practices and Responsibilities (PPR) course is a mandatory online qualification for individuals seeking a Commercial... More Details
  • General Nautical Terminology Propeller

    A propeller is a fan-like device that propels a boat or ship through the water by converting rotational motion into thrust. Propellers typically...

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  • General Nautical Terminology Propeller Shaft

    A propeller shaft is a long, cylindrical metal shaft that connects the boat's transmission or gearbox to the propeller. It transmits power from...

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  • General Nautical Terminology Propeller Walk

    The lateral movement of a boat's stern caused by the rotational forces of the propeller, typically noticeable when operating at low speeds or in...

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  • General Nautical Terminology Propeller Wash

    The turbulent flow of water generated by a vessel's propeller as it moves through the water, often creating strong currents and turbulence behind...

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  • General Nautical Terminology Pulpit

    A raised structure at the bow of a vessel, often made of metal, designed to provide safety for crew members working at the front of the...

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  • General Nautical Terminology Pushpit

    A sturdy, protective railing or guardrail located at the stern of a boat, often forming part of the vessel's safety framework.

    The pushpit,...

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  • General Nautical Terminology, Safety Pyrotechnic

    A device or material designed to produce light, heat, smoke, or sound through a chemical reaction, commonly used in marine signalling for...

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  • Flag / Pennant, Signals & Communication Code Flag Quebec (Q)

    The International Maritime Signal Flag Quebec.

    Meaning

    Quarantine Flag.
    My vessel is healthy and I request free pratique.

  • General Nautical Terminology Q FlagYellow flag flown from starboard spreaders or flagstaff when entering a foreign port (or Channel Isles) requesting customs clearance. Don’t remove... More Details
  • Flag Semaphore, Signals & Communication Letter Q (Flag Semaphore)
    Flag semaphore indicating the letter Q.

    Flag semaphore indicating the letter Q.

  • Morse Code, Signals & Communication Letter Q (Morse Code)

    International Morse Code sequence representing the letter Q.

  • General Nautical Terminology Quarter Berth

    A small sleeping area located beneath the cockpit on a sailing or motor vessel, typically positioned on one side of the boat's stern.

    A...

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  • Phonetic Alphabet, Signals & Communication Quebec

    Pronounced: keh-BECK

    The term for the letter Q in the NATO Phonetic Alphabet.

  • General Nautical Terminology RaceA strong tidal stream
  • Courses RadarThe RYA Radar course teaches participants to use radar systems effectively for navigation and collision avoidance. Topics include radar setup,... More Details
  • General Nautical Terminology, Safety Radar Reflector

    A passive device designed to enhance a vessel's visibility on radar systems by reflecting radar signals back to their source.

    A radar...

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  • General Nautical Terminology, Safety Radio Medical Advice Link Call (MEDILINK)

    A communication made via radio from a vessel to a shore-based medical facility or professional to seek urgent medical advice or assistance for an...

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  • General Nautical Terminology RaftTwo or more vessels tied up alongside each other
  • Abbreviation, General Nautical Terminology RAM

    A ship that, due to the nature of its work, is unable to keep out of the way of other vessels as required by the International Regulations for...

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  • General Nautical Terminology, Navigation Range of Tide

    The vertical difference between the high tide and the succeeding low tide in a specific tidal cycle.

    The range of tide is a fundamental...

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  • General Nautical Terminology Raster chartElectronic chart which is a direct copy of a paper chart with limited zooming capability
  • General Nautical Terminology, Navigation Rate (Tidal Stream)

    The speed at which a tidal stream flows, typically measured in knots.

    The rate of a tidal stream is the velocity at which the water moves due...

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  • Flag / Pennant, Signals & Communication Code Flag Romeo (R)

    The International Maritime Signal Flag Romeo.

    Meaning

    Distance (range) in nautical miles. Given using Numeral Pennants.

  • General Nautical Terminology Reach

    The point of sail where the wind is coming from the side of the boat, roughly perpendicular to the direction the boat is travelling. 

    A reach...

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  • General Nautical Terminology ReachingSailing across the wind: from about 60° to about 160° off the wind. Reaching consists of "close reaching" (about 60° to 80°), "beam reaching"... More Details
  • General Nautical Terminology Ready AboutThe helmsman’s shout that he intends to go about shortly
  • Flag Semaphore Ready (Flag Semaphore)

    The Ready (Flag Semaphore) signal shows the sender is ready to send a message. The same shape is also used for Space (Flag Semaphore) & Rest...

    More Details
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